I've thought about this a lot. What I really don't want to do is invest time in dealing with the data I don't care about. Because of the nature of spending, it tends to be pretty noisy data. When my budget isn't tight, I really don't care to track and think about every transaction. I'm just not interested in a detailed accounting of my coffee habit if at a high level my finances are on the right track.

I've taken an approach of manual entry for a few "important" categories of discretionary spending. It's been good to leave everything else for the less frequent review of my bank statements.